jaromir wrote:Maybe I overlooked something, but... I fell like the temperature - resistance table on 9th page of this thread doesn't work for me.
That is normal. Each handle has it's own table (each clone uses different RTD). That is why you have to calibrate.
The temp vs resistance curve is pretty straight between 180C (even 100C) and 450C and that is the region you want to use your iron with so you calibrate with 2 points and that's it. It's not perfectly accurate but more then enough for what it's purpose is. Below 100C the curve start to go crazy
jaromir wrote:I bought some chinese Hakko 907 soldering irons on Ebay, but the resistance at room temperature is somewhere around 60Ohm
the room temp resistance does not really help much as the curve below 100C varies hugely between clones.
Did you make the electronics? If you did select "hakko original" it might work, there are also data in there for quick and gordak iirc so try them too see what works best for you, if not you will have to calibrate your iron
look at some tables here: http://elco.crsndoo.com/wordpress/2011/ ... -lemilice/
1.7R at 27C is one table (the one in the post)
then look in comments, there is another sensor with
60R at 77.6C (I think this one is around 40R at 25C)